For example, a liquid crystal display device comprising a liquid crystal layer held between a first electrode and a second electrode, and having features that the liquid crystal layer is subjected to twisted nematic alignment, that a rotational viscosity of the liquid crystal layer is 50 to 80 mPas, that a cell gap which is the thickness of the liquid crystal layer is 2.5 to 5.0 μm, and that a potential difference between the first electrode and the second electrode is 0.2 to 8.0 V, has been disclosed.
Meanwhile, a problem arises that due to aggregation of ionic impurities in the liquid crystal layer, in a display area, a voltage holding ratio is reduced locally, and that a deterioration in display quality results from non-uniformity in display (for example, black non-uniformity in display that a part of a white display screen is displayed black) is caused.